There is need for highly efficient, regenerator-type furnaces of rotary configuration providing low-cost, efficient, high-temperature heating. It has been found that when a regenerator consisted of a loose particle bed held in solid body rotation, as in a cylinder shape, two problems resulted. Firstly, the bed porosity was quite low, for example around 40%, and the small particles of 2 mm mean diameter that were employed were very tightly packed. This offered undesirably great resistance to air flow. Secondly, the rotation rate superimposed a high tangential velocity on the incoming air which resulted in "fanning" it directly to the outlet, depriving the combustion chamber within the cylinder of oxidant. Under these circumstances, only a small flame could be maintained, but for only very small bed thickness, e.g., less than 5 mm--a thickness negligible as far as any regenerative effect was concerned. Thus, enhanced regenerative effect was not possible.